Make callers of CommandLine use it via the base:: namespace.

chrome/browser/ui/panels/panel_extension_browsertest.cc

Index: chrome/browser/ui/panels/panel_extension_browsertest.cc
diff --git a/chrome/browser/ui/panels/panel_extension_browsertest.cc b/chrome/browser/ui/panels/panel_extension_browsertest.cc
index 9e67571f2ef6a6c92095bb18f4b1a28f3af753b4..c5a88a1149a33017d5881d716a25a8fd9daf1fde 100644
--- a/chrome/browser/ui/panels/panel_extension_browsertest.cc
+++ b/chrome/browser/ui/panels/panel_extension_browsertest.cc
@@ -32,7 +32,7 @@ using extensions::Extension;
 
 class PanelExtensionBrowserTest : public ExtensionBrowserTest {
  protected:
-  void SetUpCommandLine(CommandLine* command_line) override {
+  void SetUpCommandLine(base::CommandLine* command_line) override {
     ExtensionBrowserTest::SetUpCommandLine(command_line);
     command_line->AppendSwitch(switches::kEnablePanels);
     PathService::Get(chrome::DIR_TEST_DATA, &test_data_dir_);